This invention relates to a method for development of a silver halide photographic light-sensitive material and a silver halide photographic light-sensitive material which provides negative images of markedly high contrast, negative images of high sensitivity and excellent dot image quality.
Addition of a hydrazine compound to silver halide photographic emulsions or developers has been known, for example, in U.S. Pat. No. 3,730,727 (developer comprising combination of ascorbic acid and hydrazine), U.S. Pat. No. 3,227,552 (use of hydrazine as an auxiliary developer for obtaining a direct positive color image), U.S. Pat. No. 3,386,831 (use of .beta.-monophenylhydrazide of a fatty carboxylic acid as a stabilizer for silver halide sensitive materials), U.S. Pat. No. 2,419,975, Mees' "The Theory of Photographic Process", the third edition (1966), page 281, etc.
Especially, the above U.S. Pat. No, 2,419,975 discloses formation of high contrast negative images by addition of hydrazine compounds.
That is, this U.S. patent discloses that when a hydrazine compound is added to a silver chlorobromide emulsion and development is effected with a developer of high pH of 12.8, a very high contrast characteristic of more than 10 in .gamma. value can be obtained. However, a strongly alkaline developer having a pH of near 13 is easily oxidized with air and thus unstable and cannot be stored or used for a long time. On the other hand, the super high contrast photographic characteristic of more than 10 in .gamma. value is very useful for photographic reproduction of continuous tone images or line images by dot images useful for printing plate making regardless of whether they are negative images or positive images.
For this purpose, hitherto, there has been generally used a process of development with a hydroquinone developer of extremely low in actual concentration of sulfite ion (normally less than 0.1 mole/1) with use of a silver chlorobromide emulsion containing more than 50 mole %, preferably more than 75 mole % of silver chloride (so-called lith-type development).
However, according to the above process, since the concentration of sulfite ion in the developer is low, the developer is extremely unstable and cannot be stored for more than 3 days.
Furthermore, all of the above mentioned processes require the use of silver chlorobromide emulsion relatively high in silver chloride content and hence high sensitivity cannot be obtained.
Therefore, it has been strongly demanded to provide super high contrast photographic characteristic which is useful for reproduction of dot images and line images with use of high sensitive emulsion and stable developer.
U.S. Pat. Nos. 4,168,977, 4,224,401, 4,243,739, 4,269,929, 4,272,614, 4,323,643, etc. disclose silver halide photographic light-sensitive materials which provide extremely high contrast photographic characteristic using a stable developer, but it has been found that the acylhydrazine compounds used in these photographic materials have some problems.
That is, it is known that these hydrazines generate nitrogen gas during development, which gathers in the film to become bubbles and sometimes damage the photographic images.
Therefore, there has been desired such compound which can provide the photographic characteristic of markedly high contrast even with small addition amount for not only reducing generation of bubbles, but reducing the production cost. Furthermore, if development is continued with using these hydrazines, numerous circular fogs (pepper fogs) tend to occur in the unexposed area, which seriously damage the image quality.
In addition, the conventionally used hydrazines must be used in a large amount for sensitization with high contrast and when especially high sensitivity is required, desirably the hydrazines are used in combination with other sensitizing means (for example, use of strong chemical sensitization; increasing of grain size; addition of compounds which accelerate the sensitization such as those disclosed in U.S. Pat. Nos. 4,272,606 and 4,241,164, etc.). However, use of the sensitizing means sometimes causes increase in sensitivity and fog with time during storage.
Moreover, when development is carried out using the conventional hydrazines, so-called uneven development often occurs due to uneven agitation of developer. This uneven development is conspicuous when automatic developing equipment is used and when development is intensified in order to prevent the uneven development, the pepper fogging phenomenon occurs.
Thus, there has been demanded such compound as having no problems in time stability, no problems of uneven development and pepper fogging, being effective with addition of small amount and being able to be easily produced.